The present invention relates to an optical system and a method for positioning an optical system, and more particularly, to a system and a method less affected by the unprecise dimensions of the internal members of the optical system.
In recent years, a projector has been an equipment for effectively providing information during information presentation or entertainment.
A projector incorporating the polarized light splitting characteristics of the polarization beam splitter allows a user to present his/her information over a screen. The projector has a light engine and a lens. The light engine includes a light source, a polarization beam splitter, and at least one panel. The light engine and the lens work cooperatively to form an image, i.e. the lens projects the image from the light engine onto a screen. The coordination between the lens and the light engine is very important, since it will affect directly the brightness distribution and the quality of the image on the screen.
In general, the precise coordination between the lens and the light engine depends on the precise dimensions of a lens flange, internal members, and holders of internal members of the optical system in the projector. Thus, unless the dimensions of all internal members are strictly controlled, the accumulation error or the assembly error is inevitable. However, the control of the precise dimensions of internal members leads to an undesirable increase in manufacturing costs.
In addition, since the life cycle of the polarization beam splitter is limited, the user needs to change it as required. Thus, the polarization beam splitter in the optical system is usually designed as a detachable type allowing easy replacement. Therefore this design may increase the error of the relative position between the holder of the polarization beam splitter and internal members. Accordingly, the relative position among them needs to be realigned after replacing a new polarization beam splitter. On the other hand, the replacement and alignment is generally done only by well-trained technicians, and it is complicated and inconvenient.
Accordingly, a demand for an optical system that is less affected by the unprecise dimensions of the internal members exists.
An aspect of the present invention is to solve the positioning problem within the optical system, and to reduce the error caused by the unprecise dimensions of the internal members of the optical system.
The present invention provides an optical system, which includes a first optical apparatus having a rest on a side thereof, a thrust member, and a second optical apparatus disposed between the first optical apparatus and the thrust member.
The optical system uses a force applied from the thrust member to press the second optical apparatus against the rest to maintain a desired relative relationship between the first optical apparatus and the second optical apparatus.
The present invention further provides a method for positioning an optical system that may be applied in a projector or a positioning device of the optical system. In this method, the optical system includes a first optical apparatus having a rest on a side thereof, a thrust member, and a second optical apparatus disposed between the first optical apparatus and the thrust member.
The method for positioning an optical system in the present invention includes applying a force from the thrust member to press the second optical apparatus against the rest to maintain a desired relative relationship between the first optical apparatus and the second optical apparatus.